Date of Award


Document Type

Honors Thesis



First Advisor

Shandelle Henson


During years of high sea surface temperature, food resources for glaucous-winged gulls (Larus glaucescens) are scarce. In response, male gulls cannibalize the eggs of neighbors. When this occurs, female gulls in dense areas of the colony adopt a tactic of egg-laying synchrony, in which they lay eggs synchronously on an every- other-day schedule. Field observations show that the first laid egg of each clutch is the most likely to be cannibalized. In this paper, we analyzed a discrete-time model of egg-laying behavior that tracks egg order in the nest. Using Jury Conditions, we found that the equilibrium destabilizes into a two-cycle as colony density increases through a critical value, and that the two-cycle becomes increasingly synchronous as density increases further. We demonstrated that synchronous colonies produce more eggs than non-synchronous colonies in the presence of egg cannibalism.

Subject Area

Cannibalism in animals; Eggs as food; Glaucous-winged gull--Cannibalism; Glaucous-winged gull--Eggs; Ovulation

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